﻿lxxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



hesitate before we affirm that such a period has been one of stagna- 

 tion or diminished fluctuation in the animate world. 



The identity of the fauna and flora of England and the continent 

 of Europe requires us to assign a very distant date to the period 

 when the existing species of animals and plants began to spread 

 themselves over the lands we now inhabit. At the period of such 

 migrations this island was still united with the continent, but a large 

 number of the existing species of mollusca and some other tribes of 

 marine animals can claim a much higher antiquity ; so much so, that 

 they were already created during the drift or glacial epoch, when the 

 physical geography of Europe bore no resemblance to that now 

 established. If therefore ten or twenty thousand years were added 

 to the chronology of the human period, it would still constitute a 

 mere fraction of that vast geological division of time during which 

 the species now our contemporaries have been coming into existence. 

 But how small is the progress yet made by us in ascertaining the 

 order in which the mammalia now living were created ! Some species 

 are so ancient as to have coexisted with a fauna of which nearly all the 

 species have died out, while others may be coeval in their origin with 

 man, and a few perhaps are of more recent creation. Man himself 

 has been multiplying on the earth since he entered upon it, and en- 

 larging the range of many animals, both intentionally and against 

 his will. These species occupy, together with the human population, 

 the places left vacant by such as are exterminated from time to time. 

 Whether the amount of change in those ten or twenty thousand 

 years which immediately preceded our own times has been greater 

 or less than the average mutation during equal periods of the past, 

 from the Silurian to the Pliocene era, is a point on which, in the 

 present infancy of the science, it would be idle to speculate. Of this, 

 however, we may feel assured, that the greater the identity of the 

 system of terrestrial changes, present and future, organic and inor- 

 ganic, with that which has prevailed throughout past time, the more 

 faithfully shall we be able to interpret the records of creation which 

 are written on the framework of the globe. 



In the first publication of the Huttonian theory, it was declared 

 that we can neither see the beginning nor the end of that vast series 

 of phenomena which it is our business as geologists to investigate. 



